US7155256B2 - Radio communication network system - Google Patents

Abstract

A radio communication network system provides a method of managing radio communication base stations and mobile terminals for accomplishing an access to the Internet from a mobile terminal and communications between mobile terminals. A base station management terminal, radio communication base stations, and mobile terminals reference their communication path information created by exchanging their adjacent terminal information and communication path information to ensure their respective communication paths to other terminals. Even if two mobile terminals cannot communicate due to their radiowaves failing to arrive at their destinations, the mobile terminals can provide a communication path for making communications therebetween through a communication line, the radio communication base station, and the base station management terminal.

Description

INCORPORATION BY REFERENCE

The present application claims priority from Japanese application JP2004-185791 filed on Jun. 24, 2004, the content of which is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION

The present invention relates to data transmission/reception technologies and information communication technologies between a terminal and a base station in a radio communication network.

An ad hoc network technology utilizes radio communications to build a network at a site itself at which terminals are brought together. This technology mainly features in that terminals recognize one another for connection to transmit and receive information about adjacent terminals to and from one another to build a multi-hop communication environment. In the multi-hop communication environment, terminals which cannot directly communicate with each other on the air can utilize other terminals located between these terminals as communication relay terminals to make communications therebetween.

On the other hand, a service has been provided for enabling mobile terminals to access the Internet through radio base stations installed for this purpose. For example, JP-A-2003-249937 discloses a radio communication system which addresses a situation in which a mobile terminal cannot directly communicate with a radio base station due to a difference in mode such as an infrastructure mode, an ad hoc mode and the like, a difference in radio communication frequency, and the like, and enables communications between the mobile terminal and the radio base station through an installed communication relay terminal which has a plurality of interfaces that enable communications in different modes at different frequencies, thereby permitting the mobile terminal to access the Internet.

In a well established radio communication environment which supports a number of mobile terminals, each of which can communicate with a plurality of radio base stations, a certain mobile terminal can access the Internet through a plurality of possible communication paths, giving rise to a need for selecting and setting an optimal communication path. However, the aforementioned JP-A-2003-249937 does not describe a radio base station for communications with an optimal quality or a method of selecting and setting an optimal communication path in a mobile terminal and a radio base station for sending communication packets to an Internet gateway.

Therefore, a need exists for a method of accessing the Internet from a mobile terminal at any site with a high quality, making use of a plurality of radio base stations.

SUMMARY OF THE INVENTION

The present invention provides a method of managing mobile terminals which have the multi-hop communication ability, and a radio communication base station which enables the mobile terminals to access the Internet.

The present invention provides a mechanism which permits a mobile terminal to select a communication base station which offers an optimal communication quality from among a plurality of communication base stations in a situation where a plurality of mobile terminals are in course of multi-hop communications implemented by the aforementioned ad hoc network technology.

The present invention provides a mechanism which permits mobile terminals belonging to different groups of mobile terminals from each other to communicate with each other through a wired network such as base station facilities, Internet networks and the like even if a mobile terminal belonging to a certain group of mobile terminal and a mobile terminal belonging to another group of mobile terminals cannot make multi-hop communication with each other over the air due to limitations in a radio accessible distance in a situation where a plurality of mobile terminals are making multi-hop communications implemented by the ad hoc network technology.

The present invention also provides a mobile terminal which has the ability to determine in accordance with a particular situation of the mobile terminal whether a communication should be made through a communication path provided through radio base stations and communication lines as mentioned above, or through a radio communication path implemented by the ad hoc network technology without utilizing the communication line.

The present invention also provides a mechanism which permits each mobile terminal to select and set an optimal communication path for sending communication packets to a terminal having an Internet gateway function with reference to communication path information which is created by respective mobile terminals which exchange information on their adjacent terminals.

The present invention also provides a mechanism which permits each mobile terminal to detect a communication path through which the terminal sends communication packets to a terminal which has an Internet gateway function.

With this mechanism, even if a mobile terminal cannot directly communicate with a radio communication base station, the mobile terminal can communicate with the radio communication base station through other mobile terminals, serving as relay terminals, to access the Internet.

The present invention also provides means through which a base station management terminal, a radio communication base station, and a mobile terminal exchange respective information about adjacent terminals and communication paths with one another, thereby permitting each terminal to keep track of communication paths to other terminals.

In this way, even if two mobile terminals cannot communicate with each other due to an excessively long distance beyond their accessing abilities, the mobile terminals can set up a communication path for communicating therebetween through a communication line, the radio communication base station, a base station management terminal, and even other mobile terminals.

Also, even if a mobile terminal moves between coverage areas of respective radio communication base stations, an optimal communication path can be selected for accessing the Internet.

According to the present invention, the mobile terminal can access the Internet even if the mobile terminal is located out of a coverage area of a radio communication base station.

Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an exemplary configuration of a system in one embodiment of the present invention;

FIG. 2 is a block diagram illustrating the hardware configuration of a communication terminal associated with one embodiment;

FIG. 3 is a diagram illustrating a terminal management method according to one embodiment;

FIG. 4 is a diagram illustrating another terminal management method according to one embodiment;

FIG. 5 is a diagram illustrating an Internet access method according to one embodiment;

FIG. 6 is a diagram illustrating another Internet access method according to one embodiment;

FIG. 7 is a diagram illustrating an inter-terminal communication method according to one embodiment; and

FIG. 8 is a diagram illustrating another inter-terminal communication method according to one embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

1. Basic Device Configuration

FIG. 1 is a block diagram illustrating a logical configuration according to one embodiment of the present invention.

Each ofmobile terminals37a–37c(collectively designated by37) has a radio communication function39, a communication path setting function43, and an adjacent terminal information management function45. An adjacent terminal refers to a mobile terminal which is located within one hop (which is a distance over which radiowaves can directly attain from another mobile terminal).

A plurality of mobile terminals37 can be connected to one another in radio communications. These mobile terminals37 may have a data transfer function so that they relay data, thereby enabling communications between a plurality of mobile terminals37 which are located beyond a distance over which radiowaves can directly attain. A communication path for making the foregoing communication is dynamically changed by the communication path setting function43 based on adjacent terminal information mutually transmitted and received on a periodic basis by the adjacent terminal information management functions45 of the respective mobile terminals in accordance with a change in the positional relationship between the mobile terminals37, a change in the radio communication situation, or the like.

A radio communication base station (hereinafter called the “base station”)11 can take (a) a configuration implemented by an infrastructure modecommunication base station13 andcommunication relay device15, or (b) a configuration implemented by acommunication relay device27. The infrastructure mode refers to a communication mode in which a communications is made through an access point.

Acommunication relay device15 in the base station (a) has a communicationpath setting function23, an adjacent terminalinformation management function25, and a base station radio interface directcommunication blocking function26. Theradio communication function17 comprises an infrastructuremode communication function19, and an ad hockmode communication function21 for an ad hoc mode in which a peer-to-peer communication is made with another device which has a communication function, bypassing an access point. The twofunctions19,21 can be operated in parallel.

The infrastructure modecommunication base station13 is connected to a wired network such as the Internet48(hereinafter called the “Internet”), and also communicate with the infrastructuremode communication function19. The ad hocmode communication function21 makes communications with an ad hoc mode communication function41 of the mobile terminal37.

Thebase station11 may use the base station radio interface directcommunication blocking function26 for making a setting to prevent radio communications with another base station. This setting prevents a closed communication path which would cause MAC (Media Access Control) frames and communication packets to loop around the closed communication path to result in a failed communication.

Thecommunication relay device27 in the base station (b) has aradio communication function29, communicationpath setting function23, adjacent terminalinformation management function25, and base station radio interface directcommunication blocking function26. Theradio communication function17 has the ad hocmode communication function21. Thecommunication relay device27 is connected to a wired network (Internet48) through a communication line.

In both configurations (a), (b) described above, thebase station11 has anInternet gateway function24,34. TheInternet gateway function24,34 forces thebase station11 to function as a relay point when the mobile terminal37 accesses an Internet site such as aninformation delivery server10.

A basestation management terminal1 has anInternet gateway function3, a basestation management function5, a communicationpath setting function7, and an adjacent terminalinformation management function9. TheInternet gateway function3 is provided for the basestation management terminal1 to act as a relay point when thebase station11 or mobile terminal37 accesses an Internet site such as theinformation delivery server10. The basestation management function5 manages information on communication paths to thebase station11 and mobile terminal37. The basestation management terminal1 is connected to the Internet48.

When a network such as the Internet48 intervenes between the basestation management terminal1 and thebase station11, the adjacent terminal information can be exchanged between the basestation management terminal1 and thebase station11 using a known tunnel technique or the like.

The basestation management terminal1,communication relay devices15,27 of thebase station11, and mobile terminal37 exchange the adjacent terminal information with one another, respectively, using their adjacent terminalinformation management functions9,25,45, to keep track of the network topology, and set communication paths for their associated terminals, respectively, using their communicationpath setting functions7,23,43.

FIG. 2 is a block diagram illustrating an exemplary physical configuration of a general information processing apparatus which can embody the basestation management terminal1, thecommunication relay devices15,27 of thebase station11, and the mobile terminal37.

Specifically, the illustrated information processing apparatus comprises aprocessor51 for executing aninformation processing program61; amemory53 for storing theinformation processing program61 executed by theprocessor51, and a variety of data referenced by theprocessor51; a non-volatileexternal storage device55 for storing theinformation processing program61 and a variety of data; a wiredcommunication interface unit58 for connection to the Internet48 to transmit and receive data to and from another information processing apparatus or a communication device; a radiocommunication interface device57 for transmitting and receiving data to and from another information processing apparatus or a communication device through radio communications; and an input/output device63 involved in input/output with the operator. These components are interconnected through a communication line59 such as a bus (hereinafter called the “bus”).

Theinformation processing program61 contains procedure information for implementing the respective functions listed above on an information processing apparatus, when it is executed by theprocessor51. Specifically, theinformation processing program61 implements functions for interacting with a viewer or an operator through the input/output device63 as required, inputting and outputting data between theexternal storage device55 and thememory53, reading data stored in thememory53 through the wiredcommunication interface unit58 and radiocommunication interface unit57, and transmitting data on thememory53 to another information processing apparatus.

Theinformation processing program61 may be previously stored in thememory53 orexternal storage device55, or loaded into the information processing apparatus from another device through a portable storage medium or a communication medium (a network, or a carrier wave, a digital signal and the like which propagate through a network) available for the information processing apparatus.

The respective functions described above may be implemented by dedicated hardware components.

In this embodiment, two management methods, i.e., a hierarchical management method and a non-hierarchical management method are illustrated for managing the mobile terminals and radio base stations.

In the hierarchical management method, each base station manages mobile terminals which can communicate with the base station directly or in the multi-hop mode. Specifically, (1) each base station ensures a communication path information for communicating with a mobile terminal (by exchanging adjacent terminal information with the mobile terminal). (2) Each base station transmits the communication path information to the base station management terminal. (3) The base station management terminal detects a communication path to each mobile terminal with reference to the communication path information to create communication path information.

With the foregoing configuration, the adjacent terminal information is exchanged only between a base station and those mobile stations which are accommodated in the base station. Therefore, even if there are a large number of base stations and mobile stations, the adjacent terminal information is not exchanged beyond the base station management terminal, resulting in a reduction in traffic which is caused by the exchange of the adjacent terminal information. However, the base stations and base station management terminal are required to have the functions (2), (3).

In the non-hierarchical management method, on the other hand, the adjacent terminal information is exchanged among all terminals, i.e., the base station management terminal, base stations, and mobile terminals. Therefore, when there are a large number of base stations and mobile terminals, an increase in the traffic results from the exchange of the adjacent terminal information. However, the base station and base station management terminal can be simpler in configuration because they do not require such functions as the aforementioned functions (2), (3).

2. Hierarchical Mobile Terminal Management Method

A method of managing the mobile terminals37 andbase station11 will be described with reference toFIG. 3.

(301)

Thebase station11 and mobile terminals37 repeatedly communicate their respective adjacent terminal information with each other using the adjacent terminal information management functions44 (for example, on a periodic basis) to create communication path information using the communication path setting functions23,43, respectively, and set the communication path information therein.

The adjacent terminal information includes (1) the address of a terminal which has transmitted the adjacent terminal information (adjacent terminal information originating terminal); (2) the addresses of terminals which are adjacent to the terminal which has transmitted the adjacent terminal information; (3) a situation as to how the terminal which has transmitted the adjacent terminal information is located with respect to the “terminals adjacent to the terminal which has transmitted the adjacent terminal information” (for example, the adjacent terminal information can be communicated in two directions, the adjacent terminal information can be communicated only in one direction, the adjacent terminal information has not been communicated for a certain period, and the like), and the like.

The adjacent terminal information, when communicated, can be contained, for example, in a communication packet such as OSPF (Open Shortest Path First) which is a known protocol implemented in routers, “Hello Message” repeatedly communicated between devices in OLSR (Optimized Link State Routing Protocol), which is a routing protocol of the ad hoc network, and the like.

Each of the communication path setting functions23,43 determines a communication path upon transmission of communication packets in accordance with the type of a communication path (whether it consists only of a radio communication path or includes a wired communication path), the number of times of hopping until a destination node, the amount of a remaining battery in a communication relay terminal, a radio field strength between terminals in communication, the communication performance such as a delay time between the terminals in communication, throughput, packet loss rate, and jitter, and so forth.

The adjacent terminal information may be communicated at regular intervals or at a period which is varied in accordance with at least one of combinations among a moving speed of the mobile terminal and its changing rate, and a radio field strength associated with adjacent terminals and its changing rate.

(302)

Each of the base station11 (ST−x), (x=A, B, . . . ) repeatedly transmits its communication path information65 (TABLE (ST−x)) to the base station management terminal1 (for example, on a periodic basis)

(303)

The basestation management terminal1 repeatedly creates communication path information TABLE (Adm) to each of the mobile terminals37 using the communication path information TABLE (ST−x) sent from each base station, and sets the communication path information TABLE (Adm) therein.

3. Non-Hierarchical Mobile Terminal Management Method

A method of managing the mobile terminals37 andbase station11 will be described with reference toFIG. 4.

Thebase station B11g,mobile terminal BB37k, and basestation management terminal1 repeatedly communicate their respective adjacent terminal information with each other using the adjacent terminal information management functions25,45,9, respectively, (for example, on a periodic basis) to create their respective communication path information69 (TABLE (ST-B)),71 (TABLE (MN-B)),67 (TABLE(Adm)) using the communication path setting functions23,43,7, respectively, and set the communication path information,69,71,67 therein using the communication path setting functions23,43,7, respectively.

The adjacent terminal information may be communicated at regular intervals, or at a period which is varied in accordance with one or more of a moving speed of the mobile terminal and its changing rate, and a radio field strength associated with adjacent terminals and its changing rate.

The communication path setting functions23,43,7 reference the associatedcommunication path information69,71,67, respectively, upon transmission of communication packets, to determine communication paths in accordance with the type of a communication path (whether it consists only of a radio communication path or includes a wired communication path), the number of times of hopping until a destination node, the amount of a remaining battery in a communication relay terminal, a radio field strength between the terminals in communication, the communication performance such as a delay time between the terminals in communication, throughput, packet loss rate, and jitter, and so forth. The delay time, throughput, packet loss rate, jitter and the like can be detected using unknown techniques.

4. Method of Accessing Internet from Mobile Terminal in Hierarchical Mobile Terminal Management Method

Referring toFIG. 5, description will be made on a method of permitting themobile terminal A37mto send communication packets to theInternet gateway function3 of the basestation management terminal1 or to the Internet gateway functions24,34 of thebase stations11, and permitting themobile terminal A37mto access the Internet in the multi-hop mode, even if themobile terminal A37mis out of the coverage area of thebase station A11h.

Assume inFIG. 3, that thebase station A11handmobile terminal A37mare managed by the management method illustrated inFIG. 3.

<Internet Accessing Method>

(101)

Each of the base stations A11h,B11ihas previously set the basestation management terminal1 having theInternet gateway function3 as a default gateway in a known method. Alternatively, each of the base stations A11h,B11imay contain theInternet gateway function24,34. When a certain terminal transmits or forwards communication packets, the terminal sends the communication packets to a destination address described in the communication packets with reference to its communication path information, in which case the default gateway specifies the default destination of the communication packets, which is selected when the communication packets do not indicate a terminal to which the communication packets are transmitted (adjacent terminal).

(102)

Eachbase station11 references the communication path information TABLE (ST−x) (x=A, B, . . . ) contained therein as required, and advertises its address to all mobile terminals37 accommodated in thisbase station11 through broadcasting, multicasting or unicasting.

(103)

The communication path setting function43 of each mobile terminal37, which has received the advertisement of the address from thebase station11, references the address included in the advertisement, and also references the communication path information contained therein to select from adjacent terminals an adjacent terminal which should be assigned to be the destination for transmitting the communication packets to the advertised address, and sets this adjacent terminal as a default gateway.

For example, when themobile terminal A37mreferences the communication path information contained therein to detect, as a result, that amobile terminal B37nis an adjacent terminal for enabling the communication packets to arrive at thebase station A11h,themobile terminal A37msets thismobile terminal B37nas a default gateway.

If themobile terminal B37nalso makes a similar setting (setting thebase station A11has a default gateway which is the destination to which the communication packets should be sent), the communication packets are transmitted from themobile terminal A37mand arrive at thebase station A11hthrough themobile terminal B37n.

Since each mobile terminal repeatedly sets a default gateway (for example, on a periodic basis) for sending communication packets to the base station as described above, the mobile terminal, even distanced by two hops or more from the base station, can send communication packets to theInternet gateway 3 to access the Internet.

When a mobile terminal receives advertisements from a plurality ofbase stations11, the mobile terminal appropriately references at least one of combinations among the radio field strength from each of thebase stations11, the number of hops from each of thebase stations11, the communication performance up to each of the base stations11 (one or more combinations among a delay, throughput, packet loss rate, jitter and the like), the distance from each of thebase stations11 to the mobile terminal, the number of hops to the basestation management terminal1, and the communication performance up to the base station management terminal1 (one or more combinations among a delay, throughput, packet loss rate, jitter and the like) to select anoptimal base station11 for sending the communication packets to the basestation management terminal1.

The mobile terminal37 registers a selectedbase station11 as a default gateway for sending communication packets to the basestation management terminal1 using the communication path setting function43.

5. Method of Accessing Internet from Mobile Terminal in Non-Hierarchical Mobile Terminal Management Method

Referring toFIG. 6, description will be made on a method for enabling amobile terminal A37qto send communication packets to an Internet gateway in the multi-hop mode to access the Internet from themobile terminal A37q, even if themobile terminal A37qis located out of the coverage area of abase station A11j.

InFIG. 6, thebase stations11 and mobile terminals37 are managed by the management method illustrated inFIG. 4. With the management method illustrated inFIG. 4, the basestation management terminal1,base stations11, and mobile terminals37 have communication path information67 (TABLE (Adm)),69 (TABLE (ST−x) (x=A, B, C, . . . )),71 (TABLE (MMN−x) (x=A, B, C, . . . ), respectively.

<Internet Accessing Method>

(401)

The basestation management terminal1 references the communication path information TABLE (Adm) 73 contained therein as required to advertise its own address to thebase stations11 and mobile terminals37 through broadcasting, multicasting, or unicasting.

(402)

Each of the mobile terminals37 and each of thebase stations11 sets an adjacent terminal for sending communication packets to the base station management terminal having the address included in the advertisement as a default gateway.

For example, when themobile terminal A37qdetects that amobile terminal B37pis an adjacent terminal for enabling the communication packets to arrive at the basestation management terminal1 with reference to the communication path information contained therein, themobile terminal A37qsets thismobile terminal B37pas a default gateway.

Since themobile terminal B37pandbase station A11jalso make a similar setting (for setting a default gateway for enabling the communication packets to arrive at the base station management terminal1), the communication packets can be transmitted from themobile terminal A37qto the basestation management terminal1 through themobile terminal B37pandbase station A11j.

When all the mobile terminals and base stations repeatedly set a default gateway (for example, on a periodic basis) for enabling communication packets to arrive at the basestation management terminal1, a mobile terminal, which is distanced even by several hops from the basestation management terminal1, can send communication packets for accessing the Internet, and can therefore access the Internet.

6. Method of Communicating between Mobile Terminals in Multi-Hop Mode through Base Station, Wired Network, and Mobile Terminal in Hierarchical Mobile Terminal Management Method

Referring toFIG. 7, description will be made on a method of enabling communications between mobile terminals37 in the multi-hop mode through thebase station11,Internet48, and mobile terminal37.

Assume inFIG. 7 that thebase stations11 and mobile terminals37 are managed by the management method illustrated inFIG. 3.

<Precondition>

(201)

Each of thebase stations11 has previously set the basestation management terminal1 having theInternet gateway function3 as a default gateway.

(202)

Each of thebase stations11 references the communication path information TABLE (ST−x) (x=A, B, . . . ) contained therein, and advertises its own address to all mobile terminals37 managed by the base station itself through broadcasting, multicasting, or unicasting.

(203)

Each of the mobile terminals37 which have received the advertisement of the address from thebase station11 references the address included in the advertisement, and further references the communication path information contained therein, if necessary, to set an adjacent terminal for sending communication packets to this address as a default gateway.

In an ad hoc network, since an outgoing path is not necessarily the same as an incoming path between two terminals, the originator of an advertised address is not necessarily assigned to be a default gateway, so that every mobile terminal must reference the communication path information contained therein to set a default gateway.

<Communicating Method>

Description will be made on a communication made between a mobile terminal C (MN-C)37uand a mobile terminal A (MN-A)37sinFIG. 7.

When the mobile terminal C (MN-C)37utransmits communication packets destined to the mobile terminal A (MN-A)37s, the mobile terminal C (MN-C)37ureferences a default gateway setting item contained therein to confirm that the default gateway is abase station B11m, and then transmits the communication packets to thebase station B11m. Upon receipt of the communication packets from the mobile terminal C (MN-C)37u, the base station B (ST-B)11mreferences a default gateway setting item contained therein to confirm that the default gateway is the base station management terminal (Adm)1, and transmits the communication packets to the base station management terminal (Adm)1. In this way, the communication packets are originated from the mobile terminal C (MN-C)37uand arrive at the base station management terminal1 (204).

Upon receipt of the communication packets, the base station management terminal (Adm)1 references the communication path information TABLE(Adm) contained therein for a communication path to the mobile terminal A(MN-A)37sto confirm that an adjacent terminal for sending the communication packets to the mobile terminal A(MN-A)37sis a base station A(ST-A)111. Then, the base station management terminal (Adm)1 transmits the communication packets to the base station A(ST-A)111.

Further, the base station A(ST-A)111, upon receipt of the communication packets, references the communication path information TABLE(ST-A) contained therein for a communication path to the mobile terminal A(MN-A)37sto confirm that an adjacent terminal for sending the communication packet to the mobile terminal A(MN-A)37sis a mobile terminal B(MN-B)37t. Then, the base station A(ST-A)111 transmits the communication packets to the mobile terminal B(MN-B)37t.

Further, upon receipt of the communication packets, the mobile terminal B(MN-B)37treferences the communication path information TABLE(MN-B) contained therein for a communication path to the mobile terminal A(MN-A)37s, and transmits the communication packets to the mobile terminal A(MN-A)37s. In this way, the communication packets arrive at the mobile terminal A(MN-A)37sfrom the basestation management terminal1. (205)

The transmission of communication packets from the mobile terminal C(MN-C)37uto the mobile terminal A(MN-A)37s(return way) is performed in a similar manner to implement communications between the mobile terminal A(MN-A) and the mobile terminal C(MN-C).

In this way, communications can be made between mobile terminals in the multi-hop mode through thebase station11,Internet48, and mobile terminal37.

A plurality of candidate communication paths can exist for communications between the mobile terminal A(MN-A)37sand the mobile terminal C(MN-C)37u, such as a direct communication, or a multi-hop based radio-only communication path, as well as the communication path through thebase station11,Internet48, and mobile terminal37. In this event, an appropriate communication path may be determined in accordance with the type of a communication path (whether it consists only of a radio communication path or includes a wired communication path), the number of times of hopping until a destination node, the amount of a remaining battery in a communication relay terminal, the radio field strength between the terminals in communication, the communication performance such as a delay time between the terminals in communication, throughput, packet loss rate, and jitter, and so forth.

7. Method of Communicating between Mobile Terminals in Multi-Hop Mode through Base Station, Wired Network, and Mobile Terminal in Non-Hierarchical Mode Terminal Management Method

Referring toFIG. 8, description will be made on a method which enables communications between mobile terminals in the multi-hop mode through thebase station11,Internet48, and mobile terminal37.

InFIG. 8, thebase stations11 and mobile terminals37 are managed by the management method illustrated inFIG. 4. With the management method illustrated inFIG. 4, the basestation management terminal1,base stations11, and mobile terminals37 have communication path information67 (Table(Adm)),69 (TABLE(ST−x) (x=A, B, . . . )),71 (TABLE(MN−x) (x=A, B, C, . . . )), respectively.

<Communication Method>

A communication made between a mobile terminal C(MN-C)37xand a mobile terminal B(MN-B)37winFIG. 8 will be given as an example.

When the mobile terminal C(MN-C)37xtransmits communication packets to the mobile terminal B(MN-B)37w, the basestation management terminal1, base station A(ST-A), base station B(ST-B), and mobile terminal A(MN-A) sequentially forward the communication packets to adjacent terminals for sending the communication packets to the mobile terminal B(MN-B)37wwhich is set in the respective communication path information TABLE(Adm), TABLE(ST-A), TABLE(ST-B), and TABLE(MN-A), thereby sending the communication paths to the mobile terminal B(MN-B)37w.

Likewise, when the mobile terminal B(MN-B)37wtransmits communication packets to the mobile terminal C(MN-C)37x, the communication packets arrive at the mobile terminal C(MN-C)37x.

In this way, the multi-hop based communications can be accomplished between mobile terminals through thebase station11,Internet48, and mobile terminal37.

A plurality of candidate communication paths can exist for communications between the mobile terminal B(MN-B)37wand the mobile terminal C(MN-C)37x, such as a direct communication, or a multi-hop based radio-only communication path, as well as the communication path through thebase station11,Internet48, and mobile terminal37. In this event, an appropriate communication path may be determined in accordance with the type of a communication path (whether it consists only of a radio communication path or includes a wired communication path), the number of times of hopping until a destination node, the amount of a remaining battery in a communication relay terminal, the radio field strength between the terminals in communication, the communication performance such as a delay time between the terminals in communication, throughput, packet loss rate, and jitter, and so forth.

It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims.

Claims (10)

1. A network system in which a base station management terminal, a base station, and a mobile terminal are connected through a radio communication and a wired communication, wherein:

the base station management terminal comprises:

an Internet gateway function for relaying an access to the Internet;

a base station management function for managing communication path information of each base station;

a communication path setting function for setting a communication path to another terminal; and

an adjacent terminal information management function for managing adjacent terminal information of the base station management terminal itself and adjacent terminal information of other terminals,

the base station comprises a radio communication function, a communication path setting function, an adjacent terminal information management function, and a base station radio communication interface direct communication blocking function for preventing direct radio communication between base stations,

the mobile terminal comprises a radio communication function, a communication path setting function, and an adjacent terminal information management function, and

the base station management terminal and the communication base station exchange the adjacent terminal information with each other.

2. A radio communication network system according toclaim 1, wherein:

the base station comprises the radio communication function in a plurality of modes, and further comprises an infrastructure mode communication base station function.

3. A radio communication network system according toclaim 1, wherein:

the respective adjacent terminal information management functions of the base station and the mobile terminal transmit and receive the adjacent terminal information with each other,

the communication path setting functions of the base station management terminal, the base station, and the mobile terminal set a communication path in the base station management terminal, the base station, the mobile terminal, respectively,

the base station transmits its own communication path information to the base station management terminal, and

the base station management terminal combines the communication path information transmitted from the respective base stations to create the communication path information including the mobile terminals, and sets the communication path information in the base station management terminal itself.

4. A radio communication network system according toclaim 1, wherein:

the respective adjacent terminal information management functions of the base station, the mobile terminal, and the base station management terminal transmit and receive the adjacent terminal information with one another, and

the communication path setting functions of the base station, the mobile terminal, and the base station management terminal create the respective communication path information, and set the communication path information in of the base station, the mobile terminal, and the base station management terminal, respectively.

5. A radio communication network system according toclaim 1, wherein:

the communication path setting function determines a communication path in accordance with at least one of combinations among a communication path, the number of hops up to a destination terminal, the amount of a remaining battery of a communication relay terminal, a radio field strength between terminals in communication, and communication performance including one or more of a delay time between the terminals in communication, a throughput, a packet loss rate, and jitter.

6. A radio communication network system according toclaim 1, wherein:

the adjacent terminal information management function sets a adjacent terminal information transmission/reception period to a fixed value, or changes the period in accordance with at least one of combinations among a moving speed of a mobile terminal, a changing rate of the moving speed, a radio field strength to an adjacent terminal, and a changing rate of the strength.

7. A radio communication network system according toclaim 1, wherein:

the communication path setting function of the base station previously sets the base station management terminal having the Internet gateway function as a default gateway,

the base station management terminal references the communication path information contained therein to advertise its own address to all the mobile terminals managed thereby, and

upon receipt of the advertisement of the address from the base station management terminal, the communication path setting function of the mobile terminal references the address included in the advertisement, and references the communication path information contained therein to set an adjacent terminal for arrival at the address as a default gateway in a communication path.

8. A radio communication network system according toclaim 7, wherein:

upon receipt of advertisements of addresses from a plurality of the base stations, the communication path setting function of the mobile terminal references at least one of combinations among the radio field strength from each of the base stations, the number of hops from each of the base stations, the communication performance up to each of the base stations (one or more combinations among a delay, a throughput, a packet loss rate, and jitter), the distance from each of the base stations to the mobile terminal, the number of hops to the base station management terminal, the communication performance up to the base station management terminal (one or more combinations among a delay, a throughput, a packet loss rate, and jitter) as required to select one base station for sending a communication packet to the base station management terminal, and

the communication path setting function of the mobile terminal registers the selected base station as an adjacent terminal for enabling the packet to arrive at the base station management terminal.

9. A radio communication system according toclaim 1, wherein:

the base station comprises the Internet gateway function,

the base station references the communication path information contained therein to advertise its own address to all the mobile terminals accommodated therein, and

upon receipt of the advertisement of the address from the base station, the communication path setting function of the mobile terminal references the address included in the advertisement, and references the communication path information contained therein to set an adjacent terminal for arrival at the address as a default gate way in a communication path.

10. A radio communication network system according toclaim 1, wherein:

the communication path setting function of the base station management terminal references the communication path information contained therein to advertise its own address to the base station and the mobile terminal, and

the communication path setting function of each of the mobile terminal and the base station sets an adjacent terminal for arrival at the base station management terminal having the address included in the advertisement as a default gateway in a communication path.

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